1/* Look at first character in UTF-16 string.
2   Copyright (C) 1999-2000, 2002, 2006-2007, 2009-2010 Free Software
3   Foundation, Inc.
4   Written by Bruno Haible <bruno@clisp.org>, 2002.
5
6   This program is free software: you can redistribute it and/or modify it
7   under the terms of the GNU Lesser General Public License as published
8   by the Free Software Foundation; either version 3 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public License
17   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
18
19#include <config.h>
20
21/* Specification.  */
22#include "unistr.h"
23
24int
25u16_mblen (const uint16_t *s, size_t n)
26{
27  if (n > 0)
28    {
29      /* Keep in sync with unistr.h and utf16-ucs4.c.  */
30      uint16_t c = *s;
31
32      if (c < 0xd800 || c >= 0xe000)
33        return (c != 0 ? 1 : 0);
34#if CONFIG_UNICODE_SAFETY
35      if (c < 0xdc00)
36        {
37          if (n >= 2
38              && s[1] >= 0xdc00 && s[1] < 0xe000)
39            return 2;
40        }
41#else
42        {
43          if (n >= 2)
44            return 2;
45        }
46#endif
47    }
48  /* invalid or incomplete multibyte character */
49  return -1;
50}
51